Sinker operating mechanism and method of knitting



A Jan.- 8`f1`063 A. F. 'CRATER 3,071,947

SINKER OPERATING MECHANISM AND METHOD OF KNITTING ELE- 2L m4 S 2l /9 ,/6 A [7 ,//5 Hummm m 2 FLE- 5 29 IN V EN TOR.

TTORNE Y `hosiery and the like.

United States Patent O i 3,071,947 SINKER OPERATING MECHANISM AND METHOD F KNITTING Alson F. Crater, Ashehoro, N.C., assigner of one-third to Thomas C. Hollingsworth and one-third to Herman M. Routh, both of Asheboro, N.C.

Filed Mar. 16, 1960, Ser. No. 15,423 7 Claims. (Cl. 66-107) The instant invention relates to improvements in circu lar kn1tt1ng machines and particularly in machines adapted .for knitting fine gauge womens hosiery and to a method of knitting thereon.

ln the normal operation followed for many' years in the knitting of fabrics on such machines the yarn is drawn to form the stitch loops over the noses of the sinkers, this method having proved quite satisfactory in the production of relatively coarse gauge fabrics Vsuch as mens This conventional method of loop drawing has not, however, proved equally as effective in the knitting of sheer fabric such as womens nylon hosiery for which generally a 400 needle machine employing yarn as fine as denier or less is used. The problem lies in the difficulty of obtaining uniform loop structure by the conventional method, the lack of uniformity in this respect, unobservable for all practical purposes in the coarser gauge goods, showing up in the form of streaks or other defects in the sheerer goods.

Heretofore it has been known for the purpose of obtaining a clearer stitch and more uniform fabric to modify the operation, specilically the sinker operation, of the machine to employ portions of the Ibacks of the nebs of the sinkers rather than the noses or platforms thereof in the stitch drawing function. The resulting method of knitting has been quite effective in obtaining uniformity of loop size and in otherwise overcoming the disadvantages of the regular method of knitting but at the same time has required the substitution of a special sinker cap embodying a hopper cam constituting a portion of the cam track for the sinkers, the flopper cam being movable between positions in which it in part defines the usual cam track and in part in which it defines a special cam track for imparting an earlier forward movement of the sinkers to position them for taking the lyarn behind their nebs. The movement ofthe flopper cam between the two positions is needed as it has been found that the regular method of drawing stitches must still be used in the knitting of the heel and toe and in the make-up courses. The required additional mechanism, which has also included linkage extending between the flopper cam and a lever adapted to be contacted by a special cam on the main pattern drum of the machine to move the flopper cam between its different positions at the required time, has added substantially to the cost of the machine and particularly has proved expensive in the conversion of existing machines. Also operational difficulties occur at times in the shifting of the flopper cam.

The principal object of the instant invention is the provis-ion of an improved and Vsimplified modification of a conventional circular knitting machine to enable the machine to operate in both methods of stitch drawing with means for shifting from one to the other under pattern control.

Another object of the invention is the provision of means for this purpose which eliminates the necessity of changing the sinker cap or other normal operating elements of the machine.

Briefly stated the invention resides in part in the utilization of a present characteristic of circular knitting machines, namely, the shiftability of the sinker cap thereof, and more particularly resides in the incorporation in such machine of means under pattern control to shift the sinker cap and hence the sinker cams at certain times during the knitting cycle. The sinker cap is shifted by the added means in a clockwise direction, that is, in a direction opposed to the direction of rotation of the cylinder during the formation of rotary knit or rundown fabric to alter the relationship between the paths of the sinkers and needles to an extent that the sinkers are advanced at the time the yarn is laid and the stitches or loops are drawn in the back of the sinker nebs in a manner similar to that accomplished by the known method employing a flopper cam, hereinabove referred to. As is well known in the conventional operation of circular knitting machines shifting of the sinker cap occurs when the direction of rotation of the needle cylinder is changed as in reciprocating knitting, the extent of shifting being controlled by bumper screws on the sinker cap adapted to contact a stop carried in a fixed position. For the purpose of the instant invention the extent of shifting of the sinker cap in a clockwise direction isgreater than normally allowed by the bumper screw and stop and hence the bumper screw controlling such shifting must be backed off fartherthan'usual. On the other hand when the machine goes into reciprocating knitting with the stitches drawn as is conventional `over the platforms or noses of the sinkers the sinker cap must be retainedv in its usual position. To enable the sinker cap to function as required a supplementary stop is employed in accordance with the instant invention, the stop being movable .under pattern'control intoA a position between theconventional stop and the bumper screw during reciprocatingknitting.

My invention will be more fully understood and further objects and advantages -will become apparent when reference is made to the more detailed description which is to follow and to the accompanying drawings in which:

FIGURE l is a diagrammatic View illustrating the paths of movements of the needles and sinkers during normal operation of a circular knitting machine;

FIG. 2 is a detail View illustrating the position of a sinker and needle during stitch drawing operations with the sinker and needle paths in the relative positions of FIG. l;

FIG. 3 is a view similar to FIG. 1 illustrating the relative positions of the sinker and needle paths upon the shifting of the sinker capl to perform knitting operations in accordance with the instant invention;

FIG. 4 is a view similar to FIG. 2 illustrating the positions of a needle and sinker during the drawing of a stitch with the sinker and needle paths in the relative positions illustrated in FIG. 3;

FIG. 5 is a diagrammaticelevational view of a circular knitting machine with parts omitted and disclosing the sinker cap shifting means of the instant invention;

FIG. 6 is a plan view of a circular knitting machine l disclosing features of the instant invention incorporated ated in circular knitting machines of other makes and types.

Machines of the type referred to are well known and i only such parts have been illustrated in the drawings and will be described hereinafter as are necessary to an understanding of the invention. The machine includes a rotatable slotted needle cylinder 1 containing the usual latch needles 2 defining a circle of needles, the needles being adapted for vertical movements at one or more yarn feeding and knitting stations between latch clearing, yarn taking and stitch drawing positions by suitable cams (not shown). The machine also includes a slotted sinker ring 3 mounted adjacent the upper end of the needle cylinder for rotation therewith, the sinker ring carrying a circle of sinkers 4 mounted in the slots thereof and adapted for movements in the slots between advanced and retracted positions under the control of sinker cams (not shown) carried by a sinker cap 5. The sinker cap is mounted on the sinker ring and adapted to be frictionally engaged thereby for movement therewith to the extent permitted by a stop 10, mounted in fixed position on a non-rotatable base or platform 11, and by adjustable bumper screws 12 and 13 carried by the sinker cap. In the normal operation of the machine in rotary or run-down knitting such as employed for the leg of a stocking the needle cylinder and 'sinker ring are rotated together in a counterclockwise direction, the sinker ring carrying the sinker cap therewith until its bumper screw 12 contacts stop 10', the sinker cap thereafter remaining stationary during the continuation of knitting.

The relative paths of the needles and sinkers at the knitting station or stations during such normal circular knitting is illustrated in FIG. 1 by the lines N and S, respectively. As there shown the needles 2, which are moving in the direction indicated by the arrow, follow the path N in which they are first raised to a maximum or latch clearing height 16 at which the previously formed fabric loops held thereby are brought below the latches thereof. They are then, as they approach the knitting station, partially lowered to yarn taking level 17 at which level the yarn Y is fed thereto as by a yarn feed finger 14 the needles thereafter being lowered to their lowest position 18 while performing their stitch drawing and knitting functions. With the sinker cap positioned for normal operation by contact of the bumper screw 12 with the stop the sinkers move through their path S from an advanced position 19, i.e. one in which they are projected toward the center of the needle cylinder, thence as they approach the knitting station and suitably while the needles are at their latch clearing height, to a retracted position 21 in which they are retained during the yarn feeding and stitch drawing operations whereby the yarn is laid and the stitches are drawn over the noses or platforms 22 and in front of the nebs 23 of the sinkers as illustrated in FIG. 2. Following movement of the needles to their lowest position 18 the sinkers are again advanced to their position 19 to catch and hold the new stitches in the throats thereof as the needles are raised to position 16.

When the stocking leg is completed the machine is clutched into reciprocatory operation and auxiliary knitting cams are brought into operation whereby the needles move through their stitch drawing and knitting waves during strokes in both directions of reciprocation. As the needle cylinder reverses direction in the successive strokes the sinker cap is shifted through its frictonal contact with the sinker ring between positions as determined by the bumper screws 12 and 13 and stop 10 to maintain the relative sinker and needle paths, i.e., to cause the stitches to be drawn over the noses of the sinkers (FIG. 2) in both directions of knitting.

For the purposes of the instant invention the sinkers are of the type having a flat portion 24 behind the neb 23 at substantially the height of, or slightly higher than, the nose or platform 22 as shown for example in patent to Fregeolle No. 2,374,857 issued May 1, 1945 which describes the known method of knitting behind the sinker nebs previously referred to. In the present method during l at 42 to a member 43 secured to the platform 11.

the operation of the machine for making a circular fabric, for example in the knitting of the leg with the exception of the make-up courses, which are preferably knit in a conventional manner over the noses of the sinkers, the position of the sinker cap S is shifted in a clockwise direction so that the relative positions of the sinker and needle paths, S and N respectively, are as illustrated in FIG. 3. Thus in the shifted position of the cap the sinkers are moved from their retracted positions 21 to their fully advanced position before the stitches are drawn by the needles 2 whereby the stitch drawing occurs behind the nebs 23 of the sinkers as illustrated in FIG. 4. In other words a similar knitting procedure is followed as in the known method of knitting behind the sinker nebs previously described.

For the purpose of shifting the sinker cap in the clockwise direction at the desired times the additional mechanism illustrated particularly in FIG. 5 is employed. This mechanism comprises a lug 25 secured to the sinker cap and a lever 26 pivoted as at 27 to a tixed portion of the machine, the lever including an arm 28 having a downwardly projecting end adapted to ride on and off cams 29 on a conventional pattern drum 3G of the machine. The upper end of lever 26 and lug 25 are connected by a link 31 the ends of which are suitably passed through bores formed in a pin 32 rotatably carried in the upper end of lever 26 and the projecting end 33 of lug 25. Collars 34 are mounted on the ends of the link whereby they may be adjustably positioned to actively control the effective length of the link, the collars being maintaied in their adjusted position as by set screws 36. A tension spring 37 is connected at one end to lever 26 above the pivot point 27 and at its other end to a lixed portion of the machine, the spring urging the upper end of the lever to the right as viewed in FIG. 5.

As will be apparent when, during counterclockwise rotation of the needle cylinder and sinker ring, drum 30 is shogged to bring a cam 29 on the pattern drum beneath the end of arm 28 the upper end of lever 26 is swung to the left as viewed in FIG. 5 to, through the medium of link 31, shift the sinker cap in a clockwise direction against the frictional drag of the sinker ring and the tension of spring 37 and maintain it in such position as long as the end of arm 28 rides on the camt When arm 28 rides olf the cam the tension of spring 37 swings the upper end of lever 26 to the right and permits the sinker cap to be rotated through its frictional contact with the sinker ring until bumper screw 12 again contacts stop 10.

Inasmuch as the shifting of the sinker cap as described above to bring about the relationship between the paths of the sinkers and needles illustrated in FIG. 3 requires an abnormal movement of the sinker cap in a clockwise direction bumper screw 13 must be backed olf from the position in which it is normally set. However during reciprocatory knitting the cap must still be prevented from rotating in a clockwise direction during a reverse stroke to an extent beyond that permitted by the conventional setting of the bumper screw. In order to provide for the latter, without requiring constant adjustment of the bumper screw as the machine shifts between rotary and reciprocatory operations, an auxiliary stop 40 is employed for insertion against the stop 10 and between it and bumper screw 13 when the machine is shifted to reciprocatory operation, the auxiliary stop being of a width equal to the distance that the screw is backed olf from its normal setting. Auxiliary stop 40 suitably comprises the inwardly projecting end of a lever 41 pivoted The movement of the auxiliary stop 40 into an operative position between the stop 10 and bumper screw 13 and away therefrom can be controlled by suitable auxiliary linkage and levers similar to that illustrated at 26 and 31 but preferably, to avoid the inclusion of such additional mechanism, means presently on circular knitting machines of the type referred to is adapted to this purpose. Thus similar knitting machines of the type described have what is termed a gravity rod 44 mounted for vertical movements under the control of the main pattern drum and normally employed for shifting certain cams and droppers into and out of operation in preparation for reciprocatory knitting and at the end of reciprocatory knitting respectively, all as disclosed in patent to Page et al. No. 1,841,205 issued January l2, 1932 to which reference may be made for details of construction and operation. As disclosed in said patent and in the instant application gravity rod 44 has secured thereto at its upper end a lever 45 serving when the rod is moved upwardly to move the dropper pick into operative position for reciprocatory knitting. For the purposes of the instant invention arm 45 is also used to control the positioning of auxiliary stop 40. Thus arm 45 is provided with a laterally extending pin 46 for contact with one arm of a lever `47 pivoted as at 48 to a lug 49 supported from the ring I11. The arm of lever 47 on the other side of the pivot 48 is connected by a link 50 to an ear 52 extending inwardly from the lever 41 above the pivot 42 thereof. A tension spring 53 with its ends secured to the lever and a fixed part of the machine tends to bias lever 41 to position stop 40 between stop 10 and bumper screw 13. As will be understood, upon upward movement of gravity rod `44 in preparation for reciprocatory knitting, pin 46 moves upwardly permitting lever 47 to swing on its pivot and lever 41 to swing toward the machine Iunder the influence of spring 53 to operatively position auxiliary stop 40 between stop 10 and bumper screw 13. Upon the return of the machine to circular knitting gravity rod 44 is moved downwardly to move the cams and widening picks it controls out of operation such downward movement at the same time depressing the end of lever 47 and, in turn, causing arm 41 to swing outwardly on its pivot 42 and move the auxiliary stop 40 to an inoperative position.

`In the knitting of a stocking fabric in accordance with the instant invention the make-up courses are suitably knitted with the machine in normal operation, that is, with arm 28 of lever 26 off of cam 29 whereby the sinker cap is in its usual position with bumper screw 12 against stop 10, the relative positions of the needles and sinkers being that disclosed in FIG. 1. Upon completion of the makeup courses the pattern drum is shogged to cause arm 28 to ride upon a cam 29 with the result that the sinker cap is shifted in a clockwise direction until the sinker and needle paths have the relationship illustrated in`FIG. 3 and the loops are drawn behind the nebs of the sinkers as illustrated in FIG. 4. This operation is continued until the heel is reached at which time the pattern drum is again shogged to move cam 29 out from under arm 28 and permit arm 26 to swing to the right as illustrated in FIG. 5 under the influence of spring 37 whereby the sinker cap, due to its frictional contact with the sinker ring is shifted in a counterclockwise direction until bumper screw 12 is again brought against stop 10. During the circular knitting, gravity rod 44 has been maintained in its lowered position in which it holds the end of lever 47 depressed and, through link 50 and arm 41, the auxiliary stop 40 inoperative. At the time the machine is clutched into reciprocatory motion gravity rod 44 is raised allowing lever arm 47 to swing on its pivot and arm 41 to be swung inwardly by tension spring 53 whereby auxiliary stop 40 is placed in operative position between bumper screw 13 and stop 10. Reciprocatory knitting then proceeds during the formation of the heel. Upon completion of the heel the rod 44 is moved to its lowered position to move the auxiliary stop 40 to inoperative position and a second cam 29 on the pattern drum is moved beneath arrn 28 `on lever 26 to again shift the sinker cap clockwise to resume knitting over the backs of the sinkers during the formation of the foot of the stocking. Upon reaching the toe, arm

`10 and auxiliary stop 40 is Vagain inserted between stop 10 and bumper screw 13 to prepare, as before, for

' reciprocatory knitting.

Having thus described my invention in rather complete detail it will be understood that these details need not be strictly adhered to and that various changes and modifications may be made all falling within the scope of the invention as defined by the following claims.

I claim:

1. In a circular knitting machine including a rotatable circle of needles, a rotatable sinker ring, sinkers having nebs mounted therein for advancing movements toward and retracting movements away from the center of the needle circle, a shiftable sinker cap including means for causing said advancing and retracting movements of the sinkers, a stitch drawing station and means for feeding yarn to said needles and sinkers thereat, the improvement comprising means for shifting said sinker cap to and holding it in a position in Which said sinker advancing and retracting means maintain said sinkers in a retracted position during the stitch drawing operation upon rotary movement of said circle of needles and said stitches are drawn forwardly of said sinker nebs, and additional means for shifting said sinker cap to and holding it in a position in which said sinker advancing and retracting means maintain said sinkers in their advanced position during said stitch drawing operation upon rotary movement of said circle of needles and said stitches are drawn rearwardly of the sinker nebs.

2. In a circular knitting machine as defined in claim l, pattern operated means for controlling the operation of said additional sinker cap shifting and holding means.

3. In a circular knitting machine as defined in claim 1, in which said additional sinker cap shifting and holding means includes a pattern drum, a lever operated by said drum, a member secured to said sinker cap, and means connecting said lever to said member.

4. In a circular knitting machine as defined in claim 1, in which said circle of needles is adapted for both rotary and reciprocatory movements and said machine includes cooperating stop means for limiting the extent of shifting of said sinker cap during said rotary and reciprocatory movements, the further improvement comprisingmeans for modifying the operation of said stop means when said sinker cap is in said position to which it is shifted and held by said additional means.

5. In a circular knitting machine as defined in claim 4, in which said cooperating stop means comprises a fixed stop, and auxiliary stop, and adjustable members on said sinker cap, one of said adjustable members for contact with said fixed stop and the other of said adjustable members for contract with said auxiliary stop, and said modifying means comprises pattern controlled means for moving said auxiliary stop between an inoperative position and an operative position for contact with said other adjustable member.

6. The method of knitting on a circular knitting machine adapted for rotary operation for run-down knitting and for reciprocatory operation for reciprocatory knitting, said machine having a circle of needles, a sinker ring, sinkers having nebs mounted in said sinker ring for advancing and retracting movements toward and away from the center of the needle circle, a shiftable sinker cap including means at a fixed location relative thereto for causing said advancing and retracting movements of the sinkers, a stitch drawing station and means for feeding yarn to the sinkers thereat, the steps comprising positioning said sinker cap to cause said sinker advancing and retracting means to advance said sinkers at said stitch drawing station to cause the stitches to be drawn behind the nebs thereof during rotary operation, knitting a fabric section, shifting said cap to cause said sinker advancing and retracting means to retract said sinkers at said stitch to be drawn in front of the nebs of the sinkers during reciprocatory operation.

References Cited in the ile of this patent UNITED STATES PATENTS Lawson etal May 3, 1938 Kale et al. Nov. 24, 1959 

1. IN A CIRCULAR KNITTING MACHINE INCLUDING A ROTATABLE CIRCLE OF NEEDLES, A ROTATABLE SINKER RING, SINKERS HAVING NEBS MOUNTED THEREIN FOR ADVANCING MOVEMENTS TOWARD AND RETRACTING MOVEMENTS AWAY FROM THE CENTER OF THE NEEDLE CIRCLE, A SHIFTABLE SINKER CAP INCLUDING MEANS FOR CAUSING SAID ADVANCING AND RETRACTING MOVEMENTS OF THE SINKERS, A STITCH DRAWING STATION AND MEANS FOR FEEDING YARN TO SAID NEEDLES AND SINKERS THEREAT, THE IMPROVEMENT COMPRISING MEANS FOR SHIFTING SAID SINKER CAP TO AND HOLDING IT IN A POSITION IN WHICH SAID SINKER ADVANCING AND RETRACTING MEANS MAINTAIN SAID SINKERS IN A RETRACTED POSITION DURING THE STITCH DRAWING OPERATION UPON ROTARY MOVEMENT OF SAID CIRCLE OF NEEDLES AND SAID STITCHES ARE DRAWN FORWARDLY OF SAID SINKER NEBS, AND ADDITIONAL MEANS FOR SHIFTING SAID SINKER CAP TO AND HOLDING IT IN A POSITION IN WHICH SAID SINKER ADVANCING AND RETRACTING MEANS MAINTAIN SAID SINKERS IN THEIR ADVANCED POSITION DURING SAID STITCH DRAWING OPERATION UPON ROTARY MOVEMENT OF SAID CIRCLE OF NEEDLES AND SAID STITCHES ARE DRAWN REARWARDLY OF THE SINKER NEBS. 